He entered politics through trade union activities and joined State Congress in 1938. In 1940, he became a member of the Communist Party of India (CPI). During his 40 years as a politician he was imprisoned for five years and six months and was in hiding for four and half years. He was a state secretariat member of the CPI in 1957.[14] He is the only living Keralite among the 32 members who left the CPI National Council in 1964 to form the CPI(M). He was Secretary of the Kerala State Committee between 1980 and 1992. Since 1985 he is the member of the CPI(M) Polit Bureau until he was removed as a party disciplinary action. He is the senior most leader of CPI(M) in India.